PSELLUS, CONSTANTINUS (MICHAEL): Byzantine philosopher and theologian; b. either at Constantinople or Nicomedia 1018; place and date of death unknown. He received his early education from his mother, studied philosophy, and learned the rudiments of law from the later patriarch, Johannes Xiphilinos. For a time he practised law, then entered the public service under the Emperor Michael the Paphlagonian and, except for a brief period which he spent as monk on the Bithynian Olympus, remained in official life either as professor of philosophy in Constantinople or as imperial minister. He lived in the most corrupt time of the Byzantine court and is charged with ambition, vanity, and servility; but he was the most learned man of his time and one of the greatest of Byzantine scholars. His philosophical position as a student and admirer of Plato was not acceptable to the orthodoxy of his day; hence his permanent influence was hardly commensurate with his attainments or his great gifts.

Relatively few of Psellus' theological writings have been printed (cf. the collection in MPG, cxxii. 477-1186; and in K. Sathas, Mesaiônikē Bibliothēkē, vols. iv.-v., Paris, 1874-76). They include an exposition of the Song of Solomon, which follows Gregory of Nyssa, Nilus, and Maximus, with original thoughts added in verse. A dialogue "On the Agency of Demons" (MPG, cxxii. 537-920) between a Thracian and "Timotheos" is the chief source of knowledge of the Thracian Euchites of the eleventh century. Certain memorial addresses--on Symeon Metaphrastes (MPG, cxiv.); on Gregory of Nyssa, Basil of Cæsarea, John Chrysostom, and Gregory Nazianzen; on the patriarchs Michael Cærularius, Konstantinos Lichudes, and Johannes Xiphilinos are also important for church history. The "Various Teachings" is a compendium of theology and Christology, anthropology and ethics, with metaphysics, astronomy, and cosmology intermingled; as printed by Migne this work may be composite. The treatise "On the Definition of Death" and "What do the Greeks Believe about Demons?" approach the domain of philosophy, and the "Opinions about the Soul" and the commentary "On Plato's Generation of the Soul" are philosophical. A large number of spiritual discourses, observations on Old-Testament topics, on the Fathers, etc., is still in manuscript. Psellus also wrote poetry, sometimes in satirical vein which shows no respect for the Church. He was one of the first of the Byzantines to turn proverbs and popular sayings to moral instruction, and herein founded or refounded a special class of literature (cf. K. Krumbacher, Mittelgriechische Sprichwörter, Munich, 1893). Of his non-theological writings all that need be mentioned here are his Chronographia, comprising the years 976-1079 (published by J. B. Bury in his Byzantine Texts, London, 1899), and his numerous letters.